Acute respiratory infections (ARI) result in ~ 1.9 million childhood deaths per year in developing countries, 20% of the deaths are in India. Viruses were found in 45 % of children hospitalized with ARI in India. The expense of many molecular diagnostic tools has limited their use in developing countries. Reverse-transcription loop mediated isothermal amplification (LAMP) is a novel technique that can amplify RNA with high specificity, efficiency, and rapidity at a low cost. Aim 1. Develop a sensitive, specific, low-cost molecular diagnostic assay for respiratory virus detection. LAMP assays will be established for respiratory syncytial virus (RSV), metapneumovirus (MPV), and parainfluenza virus (PIV). Visual and machine detection for LAMP assays will be evaluated. Quantitative real-time LAMP assays will be developed. Aim 2. Evaluate the sensitivity, specificity and cost-effectiveness of LAMP for the detection of respiratory viruses in clinical samples. Lamp assays will be compared to RT-PCR for virus detection. The samples to be used are from a unique collection of clinical samples available in Delhi, including prospectively collected samples from studies of ARI in children. Quantitative real-time LAMP will be used to test the hypothesis that viral loads correlate with disease severity. This proposal is responsive to PAR-07-216, Indo-US Program on Maternal and Child Health and Human Development Research. It is a collaborative project involving U.S. and Indian investigators to enhance child health, disease prevention, product development and technology transfer. The goal is to translate new molecular detection techniques into practical tools for rapid respiratory virus diagnosis. The proposed studies are relevant to public health because respiratory virus infections are an important cause of disease among children in both developed and developing countries. Improved virus detection methods can improve respiratory virus diagnosis and support studies of respiratory virus pathogenesis along with antiviral and vaccine development.